Automatic grounding relay



Sept. 17, 1929. w. L. HINTZ AUTOMATIC GROUNDING RELAY \IIIIIIIH Filed June x2'7, 1927 Patented Sept. 17, 1929 UNITED STATES WALTER I]. HINTZ, OF MADISON, WISCONSIN ASSIGNOR TO TAYLOR IPANY, OF MADISOJQI, WISCONSIN.

PATENT F 1 AUTOMATIC enounnrns nntnr I Application filed June 27,

This invention relates to improvements in automatic grounding relays. i

The principal object 01 the invention is to provide a relay which is adapted to connect the antenna system of a radio receiving set with the ground, automatically, upon opening the battery circuit of the set as when the radio is shut off by means of the ordinary battery switch. Other more specific objects relate to various features of construction and arrangement of parts which will become apparent from a consideration of the following specifications and accompanying drawings, wherein one embodiment of the invention is illustrated.

Fig. 1 is a longitudinal sectional View through the relay associated with a conventional radio receiving set shown diagrammatically.

Fig. 2 is a sectional view taken on line 2-2 of Figure 1.

In the drawings 10 is a suitable casing preferably of bakelite or other insulating material. having a cover 11 removably secured thereto by any appropriate means. To one wall of the casing 10 is secured, as by screw 12, an electromagnet 13 consisting of a soft iron core 14 and winding 15. The elect-romagnet may be enclosed in a casing 16 if desired. The ends of the winding are connected to binding posts 17 and 18. An armature 19 is riveted to a spring arm 20 which is secured at its lower end to a terminal 21. The terminal 21 may be slotted as shown inFig. 1 to receive the end of the arm 20 which may be secured thereto, in proper position by means of rivet 22, for instance, or any other suitable construction may be employed. The opposite end 01 arm 20 carries a contact member 23 which, in the full line position shown in Fig. 1, bears against a contact 24; or antenna terminal 25, when the relay arm 20 is in the circuit closing position shown in Fig. 1.

It will be apparent that lightning or other electrical discharges will flow from the antenna 26 to the post 25 through contact members 24.- and 23 through the arm 20 to the post 21 and thencevia the conductor 27 to the ground 28.- When the current from ELECTRIC 001v:-

battery .29 to the radio set 30 is turned 2 V on by. means of the switch 31, current will flow through conductor 32 through the" coil 13 and conductor 33 to the set, thus energizing the coil which will attract the armature 19 to the'dotted line positionand thereby open the circuit from tlieanten na" to the groundgf M Q .The gap providedjbetween the contact members '23 and 24, when thearmature has beenattra'ctedfas above mentioned, is very slight "so that any unusual discharge of stray current such as a discharge oflightning by residual magnetism after the battery cir cuit has been opened. Although the relay structureelectrically connectedto' the radio set, it may. of course be mountedin or built inaspart of'said set. v a p Although I have shown certain features of my improvements for the purpose of illustratiomit will be apparentthat various changesmay be made therein without departing from the spirit of the invention and I do not/wish to be restricted to the specific form shown except where limitation thereto appears in the following claims.

What I claim is: I 1. A device of the class described comas shown is a separate I prising a switch adapted when closed for grounding the antennae of a radio receiving set, and means for electrically opening said switch by the receiving set operating current.

2. A device of the class described com prisin a casino? having antennae and groans. terininas, a. member ndrmally bridging said terminals, an electro magnet adapted for series connection with a battery of a radio receiving set, and an armature for said magnet for holding said member out of bridging relation while said battery circuit is closed.

3.. A device of the class described comprising a casing having antennae and ground terminals, a resilient member secured to one of said terminals and normallycontacting with the other, an electro-magnet in said casing adapted for series connection with a battery of a radio receiving set, and an armature on said resilient member whereby when said magnet is energized by current from said' battery said, member will be moved out of contact with said second mentioned terminal for interrupting the grounding circuit of the antennae, said arm returning to normal position when said magnet is de-energized.

at. An automatic grounding device for radio receiving sets comprising an electromagnet having a winding. and a core, an

armature movable toward said core when said coil is energized, ground and antenna terminals,-and a spring arm normally bridging said terminals said armature being riveted to said arm whereby said arm is moved to open the circuit through said terminals when said coil is energized, said rivet being of non-magnetic material and serving to space the armature from the core to prevent the retention of the arm in circuit opening position when the magnet is de-energized. r

5. A device of the class described, comprising a switch adapted when closed to ground the antennae of a radio receiving set, and means electrically controlled by the receiving set operating current for opening said switch.

6. A device of the class described, comprising a switch adapted to control the grounding of the antennae of a radio receiving set, and electro-magnetic means connected in series withtlie A circuit of the receiving set for controlling the actuation of said switch.

In testimony whereof, I have subscribed my name.

WALTER L. HINTZ. 

